Mixing system



plfil 4, '1939. I R ETZKQRN 24,152,956

MIXING SYSTEM Filed Jan. '7, 1938 Patented Apr. 4, 1939 UNITE@ STATES PATENT OFFICE Application January 7, 1938, Serial No. 183,917 In Germany January 7, 1937 11 Claims.

This invention relates to a process of mixing liquids and to an apparatus for carrying out this process.

It is the object of the invention to facilitate the mixing of liquids which occur or become available at different times or places. More particularly the invention is concerned with the mixing of batches of liquids successively produced in a continuous process, for making up for small diiferences in the composition of the successive batches occurring in the continuous chemical or other treatment, or for adjusting the properties or composition of the liquid by adding certain quantities of the same or another l5 liquid or liquids eifecting the desired properties or composition.

A special object of the invention is to mix different quantities of liquids, more particularly thick or viscid substances, mixtures, colloidal solutions and the like with a minimum consumption of energy compared to the power consumption required in the conventional large mixing l vessels.

According to this invention, the liquids or 2li batches occurring at different times or places are split up into equal portions and the single portions are delivered into upright communicating vessels or reservoirs arranged at different levels in a staggered arrangement in such a man- 30, ner that all portions of one batch of liquid take up the same level in the vessels while being at different distances from the bottoms or discharge openings of the vessels. After the different batches have been lled in, the liquid is continuously or intermittently tapped off from the bottoms of the vessels while fresh portions of the different batches of liquid are fed to the top of the vessels continuously or intermittently.

The invention will be better understood by reference to the following detailed description in connection with the accompanying drawing, showing by way of example and schematically two embodiments of my invention, viz- Figure 1 is a section through one embodiment of my invention.

Figure 2 is a longitudinal section through a preferred modification of my novel apparatus.

Figure 3 is a lateral section of the distributing device of the apparatus shown in Figure l.

Referring now to the drawing in greater detail,

and first to Figure 1 it will be seen that four upright containers or vessels 1, 2, 3, 4 are provided, having cylindrical shapes and uniform cross sections. The bottoms of the four containers are,

5,5y however, at different levels so that each of the containers 2, 3 and 4 has a capacity exceeding by the same amount the capacity of the preceding container. The level difference between the bottoms of two succeeding containers is so dimensioned that the diiierence in volume corresponds i approximately to the volume of the respective portion of the batches lled in in the mixing process.

The discharge holes arranged at the bottoms l of the containers are connected with the horil0 Zontal central pipe 9, by connecting pipes 5, 6, 1, 8. The central pipe 9 may alternately be arranged inclined or in any suitable position. Inserted in this central pipe is a feed pump IE! of any suitable description, for instance, in the 16 form of a gear pump.

When starting the mixing process, a quarter of a batch of the liquid is iirst filled into the container 4 (a). Then one quarter (b) of a second liquid batch is iilled into each of the vessels io 4 and 3 and then, one quarter (c) of a third charge or batch is filled into each of the vessels 4, 3, 2. The next portion of liquid is then distributed, at four uniform portions (I), to all of the four vessels. The four portions I accordi5 ingly are at equal levels. In the same manner, the portions II, III, IV etc. of the further quantities of liquid are distributed over the four vessels. Now, when tapping the liquid from the vessels, the level of the liquid in the four communi- $0 cating vessels sinks or falls practically uniformly so that four portions derived from four diiferent batches in the vessels are mixed in the central pipe 9. For instance, the portions I, II, III and IV of the different batches are distributed over s the four containers and thus mixed with each other. With further tapping, the portions II, III and IV of the vessels 4, 3 and 2 will be mixed with each other and with a portion of a fifth batch from the vessel l. The mixed liquid now may be taken from the central duct or delivered further by compressed air acting upon the vessels or the mixing system or by a pump Ill. The mixing process may be intensified by a filter ar rangement behind lthe pump Il) or by any other 415* suitable mechanical or chemical treatment.

It will be understood that my novel process is particularly advantageous when carried out continuously, since in this case only a single short starting period, i. e. filling in of the portions 50 a, b, c, is required only, after which operation all of the liquid batches which occur or become available can be distributed over the four vessels.

A modiiied apparatus which is suitable for caru,

rying out my novel process is shown in Figure 2. The apparatus in this instance consists of an exterior substantially cylindrical vessel II and cylindrical reservoirs or vessels I2, I3, I4, I5 positioned therein. The dimensions of these vessels are so chosen that the spaces between two level surfaces in the interior cylinder and in the annular spaces bounded by two cylinders each have the same filling capacity or volume. Advantageously, the discharge openings of the single vessels are coaxially arranged. These discharge openings may be provided with short tubular projections each of which terminates close` ly above the next lower discharge opening, as shown in Figure 2. In some instances I may provide the discharge tubes to extend through the lower discharge openings and to terminate approximately at the level of the discharge opening of the largest vessel, i. e. the lowest bottom.

The exterior vessel II may be formed as a strong-walled pressure vessel, and provided with a heating or cooling cover I6, as -shown in Figure 2. The vessels II, I2, I3, I4, I5 may alternatively be formed with a square, rectangular or polygonal cross section, provided that the filling capacity of the spaces between equal level surfaces is the same as hereinbefore described, in order to render it possible to mix equal portions of different liquids.

The modification shown in Figure 2 offers the advantage, compared to single separatelypositioned vessels, as per Figure l, that only the exterior vessel II has to withstand the pressure of the liquid, while the interior cylinders I2, I3, I4, I5 may have very thin walls, since the pressure acts upon the walls from both sides so that these interior walls are not stressed by the pressure but merely serve to guide the liquid. The hydrostatic pressure and the additional pressure, if any, will stress the exterior wall only. Moreover, only a single heating or cooling device or heat insulating cover is required.

Where it is intended to mix with each other different proportions of the different liquids or batches, the cross sections of the vessels may be varied in the Same proportion.

An automatic feeding device may be used to deliver the liquid proportionally to the vessels, consisting, for instance, of feed pumps, overfallweirs or measuring nozzles corresponding in number to the number of vessels.

Figures 1 and 3 illustrate a distributing vessel with overfallweirs, comprising a space I8 into which the liquid or liquids are delivered 'by a feed pipe I'I. The liquid falls over the upper edge of the wall I5 into the four chambers 20, 2|, 22, 23

and is thus delivered to the vessels I, 2, 3, 4 through the pipes 24, 25, 26, 2'I. The quantities of liquid delivered into each of the chambers 20, 2|, 22, 23 is proportional to the proportional length of the overfall edge I9 of the respective chamber. In order to distribute the liquid equally over the four chambers, the respective overfall edges should be equal in length.

Figure 2 shows a feeding device in the form of a distributing pipe 28 having a number of measuring nozzles 29, 3E), 3I,V 32, 33 associated to the vessels I5, I4, I3, I2, II, respectively, and effecting a uniform distribution or a distribution in any desired proportions by suitable choice of the passage cross sections.

My novel process and apparatus may be used in many industrial iields for mixing liquid or liquied substances, for instance, for mixing oil, liquid bitumen, solutions of cellulose or cellulose derivatives, such as for example solutions of acetyl cellulose of the kind used for making varnishes or lacquers, artificial silk or foils, or mixtures of synthetic fatty acids.

I claim:

l. In a process of continuously mixing liquids, the steps which comprise distributing a batch of one liquid to a plurality of vessels having their bottoms positioned at different levels and being already filled with a liquid up to a certain level, then distributing a batch of a second liquid to the said vessels in the ratios selected in the distribution of the lirst named batch, and concurrently allowing the liquids to flow through discharge pipes connected to the bottoms of said vessels into a pipe line connecting said discharge pipe with each other, and continuing said distributing and discharging operations in the ratios selected for the second batch with further batches of liquids. i i i 2. In an apparatus for mixing liquids, in combination, a plurality of reservoirs having their bottoms arranged at diierent levels in a stepped arrangement which have different capacities between the horizontal planes passing through all the reservoirs and their bottoms, pipes for connecting the said bottoms with each other and with the point to which the mixed liquids are to be delivered and means for successively distributing the component liquids of the mixture over said reservoirs in such a manner that each batch of component liquid takes up substantially the same level in all of said reservoirs.

3. In an apparatus for mixing liquids, in combination, a plurality of upright reservoirs of equal cross sections having their bottoms arranged at dilierent levels in a uniformly stepped arrangement which have different capacities between the horizontal planes passing through all the reservoirs and their bottoms, pipes for connecting the said bottoms with each other and with the point to which the mixed liquids are to be delivered and means for successively distributing the component liquids of the mixture over said reservoirs in such a manner that each batch of component liquid takes up substantially the same level in all of said reservoirs.

4. In an apparatus for mixing liquids, in coinbination, a plurality of reservoirs concentrically positioned in a common exterior vessel which have different capacities between the horizontal planes passing through all the reservoirs and their bottoms and having their bottoms at different levels so that the bottom of the innermost reservoir is at the highest level, discharge openings in said bottoms substantially coaxially positioned with respect to a common vertical axis and means for distributing the component liquids of the mixture over said reservoirs including said exterior vessel in constant proportions for the liquids consecutively distributed.

5. In an apparatus for mixing liquids, in combination, a plurality of reservoirs concentrically positioned in a common exterior vessel which have different capacities between the horizontal planes passing through all the reservoirs and their bote toms and having their bottoms at different levels so that the bottom of the innermost reservoir is at the highest level, discharge pipes in said bottoms substantially coaxially positioned and terminating substantially at the level vof the discharge opening of the next lower bottom, means for distributing the component liquids of the mixture over said reservoirs includingsaid exterior vessel in constant proportions for the liquids consecutively distributed.

6. In an apparatus for mixing liquids, in combination, a plurality of reservoirs concentrically positioned in a common exterior vessel which have different capacities between the horizontal planes passing through all the reservoirs and their bottoms and having their bottoms at different levels so that the bottom of the innermost reservoir is at the highest level, a discharge opening in the bottom of said exterior vessel, discharge pipes in said bottoms substantially coaxially positioned and terminating substantially at the level of the discharge opening in the bottom of said exterior vessel, means for distributing the component liquids of the mixture over said reservoirs including said exterior vessel in constant proportions for the liquids consecutively distributed.

7. In an apparatus for mixing liquids, in com.- bination, a plurality of reservoirs concentrically positioned in a common exterior vessel which have different capacities between the horizo-ntal planes passing through all the reservoirs and their bot-` toms and having their bottoms at different levels so that the bottom of the innermost reservoir is at the highest level, discharge openings in said bottoms substantially coaxially positioned with 'respect to a common vertical axis, means for distributing the component liquids of the mixture over said reservoirs including said exterior vessel in constant proportions for the liquids consecutively distributed, and a pressure pipe connected with the top of said reservoirs.

8. In an apparatus for mixing liquids, in combination, a plurality of reservoirs concentrically positioned in a common double-walled exterior vessel which have diierent capacities between the horizontal planes passing through all the reservoirs and their bottoms and having their bottoms at diierent levels so that the bottom of the innermost reservoir is at the highest level, discharge openings in said bottoms substantially coaxially positioned with respect to a common vertical axis and means for distributing the component liquids of the mixture over said reservoirs including said exterior vessel in constant proportions for the liquids consecutively distributed.

9. In an apparatus for mixing liquids, in combination, a plurality of communicating reservoirs having discharge openings at different levels in a staggered arrangement which have different capacities betwen the horizontal planes passing through all the reservoirs and their bottoms and means for automatically distributing each component liquid of the mixture over said reservoirs with retention of the same distribution ratio for the different liquids.

10. In an apparatus for mixing liquids, in combination, a plurality of communicating reservoirs having discharge openings at different levels in a staggered arrangement which have different capacities between the horizontal planes passing through all the reservoirs and their bottoms and means comprising overfall weirs for automatically distributing each component liquid of the mixture over said reservoirs with retention of the same distribution ratio for the different liquids.

11. In an apparatus for mixing liquids, in com.- bination, a plurality of communicating reservoirs having discharge openings at different levels in a staggered arrangement which have different capacities between the horizontal planes passing through all the reservoirs and their bottoms and means comprising calibrated measuring nozzles for automatically distributing each component liquid of the mixture over said reservoirs with retention of the same distribution ratio for the different liquids.

RUDOLF ETZKORN. 

